Mill for rolling a thin, flat product

ABSTRACT

A cluster-type rolling mill for rolling very thin sheet, strip or the like, which applies rolling force substantially over only the width of the rolled product thereby eliminating roll flexing forces conventionally existing in the rolls outside the width of the rolled product.

United States Patent lnventor John James Stone Marengo, lll. Appl. No.810,278 Filed Mar. 25, 1969 Patented Dec. 21, 197i Assignee The ArnoldEngineering Company Marengo, ll]. 1

MILL FOR ROLLING A THIN, FLAT PRODUCT 5 Claims, 2 Drawing Figs.

US. Cl 72/242 Int. Cl r B21!) 29/00 Field of Search 72/237,

[56] References Cited UNITED STATES PATENTS 2,776,586 1/1957 Sendzimir72/243 Primary Examiner-Charles W. Lanham Assistant Examiner-B. .I.Ollila Atl0meysRichard A. Speer. Vincent G. Gioia and Howard R.Berkenstock, Jr.

ABSTRACT: A cluster-type rolling mill for rolling very thin sheet, stripor the like, which applies rolling force substantially over only thewidth of the rolled product thereby eliminating roll flexing forcesconventionally existing in the rolls outside the width of the rolledproduct.

BACKGROUND OF THE INVENTION In cold rolling metal stock, such as sheet,strip, or the like, in a cluster mill, it is generally preferable toroll a flat product (i.e., one of uniform thickness and without wrinklesand buckles). In conventional rolling mills, deflection and end flexingof the rolls in certain situations result in the rolled product notbeing fiat, i.e., cambered, distorted, and nonuniform.

In the rolling of a very thin strip such as foil, deflection due torolling forces produces an exaggerated result in that a specific amountof camber constitutes a greater percentage of nonuniformity over thethickness of the strip. This problem has generated a number of solutionsto compensate for the deflection and flexing in order to roll a flatproduct. Familiar solutions for the problem all accept or even inducedeflection and flexing of the rolls and employ rolls of correctiveshapes. These corrective rolls, which may be crowns, flats and tapers,are most often used as backup rolls to reduce or counteract work rollflexing and thus produce a flat product. Beyond corrective rolls,elaborate roll bending systems may be incorporated in rolling mills tocorrect shape and eliminate work roll flexing. The grinding and honingof rolls to corrective shapes is an expensive operation requiring a highdegree of skill. The operation of roll bending devices to correct workroll flexing also requires considerable skill. In order to produce avariety of products from a mill, large numbers of corrective rolls ofvarying shape have to be maintained ready for use, thereby necessitatingexpenditure of large sums of money and time. Further, setup and start-upprocedures for various products are time consuming and also require veryhigh-skilled personnel to achieve the right combination of roll shapesto produce a specific flat product. Quite often for a new product setup,procedures are prolonged as a trial and error period and are needed toachieve the right combination of rolls to produce the new flat product.The invention herein described eliminates many of the abovedisadvantages in rolling flat sheet, strip, or the like.

SUMMARY OF THE INVENTION The present invention provides apparatus forrolling a flat product such as sheet, strip, or the like between workrolls wherein the forces for rolling the product are transmitted to thework rolls over a width substantially equal to the width of the rolledproduct. In operation of rolling mills, I have found that theapplication of rolling forces to the rolls over an area wider than thewidth of therolled product results in end flex ing of the work rollsaround the work. This roll flexing causes the work to become cambered,distorted, and nonuniform. l have also discovered that if the rollingforces are maintained uniform on the rolls over the width of the rolledstock and no rolling forces are exerted on the work rolls beyond theedges of the stock, the problem of end flexing is considerably overcome.

Accordingly, it is an object of this invention to provide a clusterrolling mill in which flexing of the work rolls is minimized.

Another object of this invention is to provide a cluster rolling millwhich omits the use of costly crowned or tapered work rolls.

Still another object of this invention is to provide a cluster rollingmill in which a minimum inventory of rolls is required to producevarious types of rolled products.

A further object of this invention is to provide a cluster rolling millwhich distributes the rolling forces equally over the rolling surface ona given roll and minimizes forces transmitted to unsupported areas of agiven roll.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of a cluster ofrolls as would be mounted in a Sendzimir Mill.

FIG. 2 is a side view of a cluster of rolls as would be mounted in aSendzimir Mill.

DESCRIPTION OF PREFERRED EMBODIMENT Referring now to the drawings andmore particularly to FIG. I, numeral 2 indicates a cluster of rolls asmay be grouped in a Sendzimir-type mill for cold rolling steel sheet,strip, or the like. An upper work roll 4 and a lower work roll 41.. aremounted in the cluster so that the work S to be rolled, e.g., strip maybe passed therebetween. Upper first intermediate rolls 6 and lower firstintermediate rolls 6L, having undercut surfaces 7, and tapered surfaces7 and force-transmitting surfaces 7" are mounted above and below, and incontact with their associated work rolls 4 and 4L. Upper secondintermediate rolls 8 and lower second intermediate rolls 8!. havingundercut surfaces 9 and force-transmitting surfaces 9 may be mounted inthe cluster above and below and in contact with the first intermediaterolls 6 and 61L. Upper saddle bearing rolls I0 and lower saddle bearingrolls 10L with pairs of backing bearings 12 and 12', 12a and 12a, and12b and 12b are mounted in the cluster above and below the associatedsecond intermediate rolls 8 and 8]..

FIG. 2 illustrates the cluster arrangement of the rolls described inFIG. I. and strip S being passed between the work rolls i and 4L.

To roll a thin flat product by use of my invention, I undercut thediameter of the upper and lower second intermediate rolls 8 and 8!. overtheir end portions thereby forming surfaces 9'. I have found thatundercutting to a depth of 0.030 inch, for example, over a distancesufficient to make the width of the force-transmitting surface 9' of theroll substantially the same as the width of the rolled product issatisfactory. Thus, to roll a 12-inch strip the second intermediaterolls would be undercut equally on both ends to a distance suflicient toleave about a l2-inch force-transmitting surface. Rolling forces areapplied to the work rolls i and 4L from the saddle bearing rolls 12through the intermediate rolls 6, 6L, 1B, and 8L. To further insure thatrolling forces will not be applied beyond the width of work product S,those backing bearings extending beyond the product (e.e., l2 and I2) Smay be backed off. This prevents the bearings 12 and 12' from makingcontact with the second intermediate rolls 8 and 8L, restrictingtransmission of the rolling forces to the width of the product S.

First intermediate rolls 6 and 6L may also be undercut to the width ofthe rolled product similarly to second intermediate rolls 8 and 8L,thereby producing force-transmitting surface 7". This may be done toboth sets as shown in the intermediate rolls 6 and 6L in the example, orto just upper or lower first intermediate 6 or 6L. By undercutting onlyone set, the inventory of various width first intermediate rolls isminimized while still extending the principle of limitation of rollforce-transmitting surface to product width into the first intermediaterolls. To enhance product edge control, the undercut first intermediaterolls 6 have a limited slight taper 7' (exaggerated in FIG. 1). Edgecontrol is required because of the tendency of the material of theproduct to move more readily under a given rolling force at the edgewhere it is unrestrained. Additionally, product to be rolled usually isnonflat and has some crown induced by previous conventional rolling andthus requires some corrective shape to remove that slight crown. Thetapering of the rolls for edge control is unlike conventional taperingto correct for roll flexing in that the taper is generally limited tothe outer 1 inch of the force-transmitting surface of the undercut firstintermediate roll and extends to a depth of only 0.0003 inch.

A rolling mill in accordance with the invention can roll a variety ofsizes and types of thin flat products and for each product the millresponds as though it were designed solely to roll the width of thatproduct by applying rolling forces only over the width of the rolledproduct. The inventory of rolls is substantially reduced and only flatrolls need be stocked, these in sufficient multiple lengths to ensurehaving all widths of rolled product which can be accommodated by asingle mill. By practicing the invention it is no longer necessary tostock a variety of shapes to achieve a deflection equal to the rollflexing induced by a product of particular width and hardness nor is itnecessary to induce roll bending through elaborate hydraulic ormechanical means. My invention provides a mill that can be set up oncefor any product of specific width avoiding the trial and error approachand further avoiding the problems of wrinkling and buckling associatedwith roll bend- While several embodiments of my invention have beenshown and described, it will be apparent that other adaptations andmodifications may be made without departing from the scope thereof.

1 claim:

l. A cluster mill for rolling articles such as strip, sheet or the like,comprising upper and lower work rolls; upper and lower bearing rolls forapplying forces for rolling; a set of intermediate rolls comprising atleast one combination of upper and lower first intermediate rolls incontact with said work rolls and at least one combination of upper andlower second intermediate rolls in contact with said bearing rolls; saidwork rolls and intermediate rolls being longer than the width ofarticles to be rolled therein; said second intermediate rolls beingundercut from the ends thereof toward the rolls center to provide aforce-transmitting surface substantially equal to the width of saidarticle to be rolled.

2. A cluster mill according to claim 1 wherein said first intermediaterolls also have a force-transmitting surface substantially equal to thewidth of said article to be rolled.

3. A cluster mill according to claim 2 wherein the roll ends of saidfirst intermediate rolls are tapered to provide a forcetransmittingsurface substantially-equal to the width of said article to be rolled.

4. A cluster mill according to claim 2 wherein the roll ends of saidfirst intermediate rolls are undercut to provide a forcetransmittingsurface substantially equal to the width of said article to be rolled.

5. A cluster mill according to claim 1 wherein said bearing rolls alsohave a force-transmitting surface substantially equal to the width ofsaid article to be rolled.

l l t i l

1. A cluster mill for rolling articles such as strip, sheet or the like, comprising upper and lower work rolls; upper and lower bearing rolls for applying forces for rolling; a set of intermediate rolls comprising at least one combination of upper and lower first intermediate rolls in contact with said work rolls and at least one combination of upper and lower second intermediate rolls in contact with said bearing rolls; said work rolls and intermediate rolls being longer than the width of articles to be rolled therein; said second intermediate rolls being undercut from the ends thereof toward the roll''s center to provide a force-transmitting surface substantially equal to the width of said article to be rolled.
 2. A cluster mill according to claim 1 wherein said first intermediate rolls also have a force-transmitting surface substantially equal to the width of said article to be rolled.
 3. A cluster mill according to claim 2 wherein the roll ends of said first intermediate rolls are tapered to provide a force-transmitting surface substantially equal to the width of said article to be rolled.
 4. A cluster mill according to claim 2 wherein the roll ends of said first intermediate rolls are undercut to provide a force-transmitting surface substantially equal to the width of said article to be rolled.
 5. A cluster mill according to claim 1 wherein said bearing rolls also have a force-transmitting surface substantially equal to the width of said article to be rolled. 